1. Field of the Invention
This invention relates to image recording apparatus such as heat-sensitive copying machines, pressure-sensitive copying machines, electrophotographic copying machines and diffusion transfer type copying machines. The invention more particularly relates to the correction of color and density in an original reading section in such an apparatus.
2. Background of the Invention
In a conventional image recording apparatus of this type a transmission type lens is provided in its section that reads the original. A flat-plate-shaped filter is disposed near the focal point of the lens. On the other hand, recently a multi-lens array has been employed as the optical system in order to meet a demand for miniaturizing the copying machine. A density filter has been disclosed in Japanese Patent Application Publication No. 37535/1983 which can be used as a filter for the multi-lens array.
On the other hand, in the case where a color copier uses only one color density filter, it is impossible to achieve color correction with high accuracy. Accordingly, the coloring is frequently not natural and the resultant copy is subtly different in color from the original.
For the accurate correction of color density, it is essential that a number of color correcting filters of different densities be employed. At least two of the different color correcting filters must be matched with each other for the proper combination of the three primary colors.
The color correcting filters must be placed in such a manner as to cover the entire width of an exposure or reading lens. Therefore, in the case in which flat glass filters are used, it is difficult in a mechanical sense to move them in the narrow space in the copying machine when they are being replaced. Heretofore, it has been considered substantially impossible to do so. In the case of a multi-lens array, the focal length is so short that it has been considered extremely difficult to provide a filter mechanism in the narrow space between the multi-lens array and the photo-sensitive material.